1. Technical Field
The present invention relates to an image forming apparatus which has a line head, and a control method for such an apparatus. The apparatus forms line latent images using the line head, develops the latent images with toner and accordingly forms an image.
2. Related Art
Known as an image forming apparatus which uses a line head in which light emitting elements such as light emitting diodes (LEDs) are arranged in rows is the image forming apparatus. The apparatus is described in JP-A-6-177431 for instance. In this apparatus, a latent image carrier such as a photosensitive member drum is driven into rotations in a sub scanning direction. A line head is disposed facing the photosensitive member drum. In this line head, plural light emitting elements are arranged in rows along a main scanning direction which is approximately orthogonal to the sub scanning direction. The elements turn on and off under control in response to an image signal. In consequence, a line latent image corresponding to the image signal is formed on the photosensitive member drum. In this manner, the light emitting elements are driven in response to an image signal covering one line while rotating the photosensitive member drum, whereby a line latent image is written. A two-dimensional latent image is thus formed on the photosensitive member drum. As the two-dimensional latent image is developed with toner, an image is formed.
Some use a line head which is comprised of multiple organic EL (electroluminescence) elements (See JP-A-2003-19826.). In such line heads, the multiple organic EL elements are arranged in rows (in a two-row staggered pattern) along the main scanning direction which is approximately orthogonal to the sub scanning direction. The elements turn on and off under control in response to an image signal. As a result, a line latent image corresponding to the image signal is formed on a photosensitive member drum.